Synchronizing arrangement for a timekeeping instrument

ABSTRACT

This invention relates to a synchronizing arrangement for a timekeeping instrument such as a wristwatch, with a pulse generator generating electrical control pulses of constant magnitude and constant but intermediate synchronizing frequency, e.g., a divided quartz frequency. The control pulses are fed to the control system of an electrodynamical actuating device for driving the instrument, having at least one driving coil as well as, movable in relation thereto, a permanent magnet system, and by means of which a mechanical oscillating member with constant synchronizing frequency and synchronizing amplitude can be set into oscillation, such oscillation being opposed by a spring member exercising a substantially constant counterforce. The arrangement includes at least one ferromagnetic adjunctive element mounted in a predetermined relationship with the coil to coact with the magnetic system and generate a nonlinear synchronizing force to facilitate synchronization of the instrument.

United States Patent [191 Barth et al.

[4 1 July 22,1975

[ SYNCHRONIZING ARRANGEMENT FOR A TIMEKEEPING INSTRUMENT [73] Assignee: Timex Corporation, Waterbury,

Conn.

[22] Filed: Jan. 11, 1974 [21] Appl. No.: 432,797

Related US. Application Data [63] Continuation of Ser. No. 265,102, June 21, 1972,

abandoned.

[30] Foreign Application Priority Data Jan. 13, 1972 Germany 2201557 [52] US. Cl. 58/28 B; 58/28 R; 58/23 R [51] Int. Cl. G04C 3/04 [58] Field of Search 58/28 B, 28 D, 28 A, 28 R, 58/107,108, 109,110,114, 23 R, 23 AC, 23 D, 23 V;318/130,l19,l26, 127,129;

[56] References Cited UNITED STATES PATENTS 2,907,940 10/1959 Beyner 4310/15 x 3,046,460 7/1962 Zemla 58/23 A x 3,597,634 8/1971 Flaig 58/23 A X FOREIGN PATENTS OR APPLICATIONS 816,803 1937 France 58/28 R Primary Examiner-Joseph W. Hartary Assistant Examiner-U. Weldon [57] ABSTRACT This invention relates to a synchronizing arrangement for a timekeeping instrument such as a wristwatch, with a pulse generator generating electrical control pulses of constant magnitude and constant but intermediate synchronizing frequency, e.g., a divided quartz frequencyThe control pulses are fed to the control system of an electrodynamical actuating device for driving the instrument, having at least one driving coil as well.as, movable in relation thereto, a permanent magnetsystem, and by means of which a mechanical oscillating member with constant synchronizing frequency and synchronizing amplitude can be set into oscillation, such oscillation being opposed by a spring member exercising a substantially constant counterforce. The arrangement includes at least one ferromagnetic adjunctive element mounted in a predetermined relationship with the coil to coact with the magnetic system and generate a nonlinear synchronizing force to facilitate synchronization of the instrument.

10 Claims, 5 Drawing Figures l SYNCHRONIZING ARRANGEMENT FOR A TIMEKEEPING INSTRUMENT This is a continuation, of application Ser. No. 265,102, filed June 21, 1972 now abandoned.

BACKGROUND OF THE INVENTION It is already known to feed driving pulses of constant frequency to timekeeping instruments that are customarily controlled by a control pulse generator. In this case, usually a mechanical oscillator is synchronized which has a nominal frequency deviating from said synchronizing frequency. In order to suppress said nominal frequency, the driving pulse is made so strong that the influence of the nominal frequency is suppressed. This arrangement has the negative characteristic that a large source of energy is required.

The synchronization of indexing devices is less complicated, but these are only utilizable for the drive of a timekeeping instrument in particular instances, because such an indexing device, due to lack of an oscillating process proper, actually has no inherent oscillation so that such oscillation need not be suppressed. But if such a movement is subjected to an impact or jolt it has the disadvantage that a driving pulse might be skipped, detrimentally affecting the accuracy of the timepiece.

SUMMARY OF THE INVENTION The object of this invention is, therefore, to provide a synchronizing arrangement which makes it possible to adjust or tune a timekeeping instrument to a specific synchronizing frequency and, in case of deviation from such frequency, to lead back the oscillating member to said frequency, whereby said synchronizing process requires a comparatively minor amount of energy.

In the above synchronizing arrangement according to this invention, this problem is solved by providing at least one ferromagnetic adjunctive element in a fixed geometric relation to the driving coil which, with the relative movement of the driving coil and the permanent magnet system, in coaction with the latter, generates a synchronizing force for adjustment .which reduces oscillating frequency when amplitude increases and increases the oscillating frequency when amplitude grows smaller, or vice versa. By this innovation it has now become possible to dimension the counterforce in such a manner that it is no longer linear, so that in case of a deviation from synchronizing amplitude a rapid restoration of and thereby adjustment to the synchronizing'amplitude and frequency again take place. It is not at all necessary in this case that greater driving pulses than'usual must be employed. The timekeeping instrument will thus be inert to jolts and impact or any other influences that'result in a deviation of synchronizing frequency and amplitude.

The following discussion will attempt to describe the mode ofoperation of the arrangement according to this invention. For simplicities sake, it is assumed that a driving coil is disposed on the oscillating member which in coaction with a stat'ionaryrpermanent magnet system provides a driving pulseapproximately in the zero position, i.e.', in the condition of the maximum velocity for every half or full oscillation. These driving pulses are monitored by the inherent oscillations of the oscillating member. If an outside pulse source delivers control pulses of specific frequency and pulse duration,

then the driving pulses will be correspondingly influenced and the oscillating member will be adjusted to said synchronizing frequency. In explaining this adjustment or tuning, it is first assumed that the oscillating member already oscillates synchronously with the synchronizing frequency and obtains timed driving pulses of such magnitude that the oscillations of the oscillating member are maintained with the constant synchronizing frequency and constant synchronizing amplitude.

In contrast to conventional watch movements, the arrangement according to the present invention is such that upon change in amplitude, e.g., due to a jolt or to impact, the counterforce acting against the oscillations generated by the movement does not remain constant, instead, it changes; For example, said counterforce increases or decreasescontinually within a definite amplitude range upon deviation from the synchronizing amplitude. Contrary to usual oscillating members, where despite change in amplitude due to an unchanging counterforce, the frequency of the oscillating member remains practically unchanged, the oscillating frequency now changes. thereby departing from the synchronizing frequency either in an upward or downward trend. Due to the variations between the synchronizing frequency and the oscillating frequency :1 corresponding phase displacement results between the monitoring pulses and the driving pulses, with the result that the driving pulses are reduced at enlarged amplitude and increased at reduced amplitude. This results in a rapid tuning of the oscillating frequency to the synchronizing frequency and to the synchronizing amplitude;

This adjustment can either be attained by monitoring by means of the rear flank or the fore flank of the monitoring pulses. This occurs in connection with the selection of the changing counterforce, i.e., whether the frequency of the oscillating member decreases or increases with changing amplitude. In every case the drive pulse at an enlarged amplitude will grow smaller for such duration until the synchronizing frequency and the synchronizing amplitude are reached. With decreasing amplitude the process works vice versa.

It is advantageous, if in the adjusting range the change in the frequency of the oscillating member as a function of the amplitude change is comparatively large, as this results in an especially rapid adjustment. In this case conveniently in the adjusting range, the change in the frequency of the oscillating member can be approximately proportional to the change in amplitude, i.e., the curve would be substantially a straight line.

As the adjunctive element is constantly unmagnetized it is preferable that the ferromagnetic element is of a material that has small hysteresis losses, e.g., similar to ferrites.

The synchronizing arrangement according to this in vention can be utilized for greatly varying synchronizing frequencies, e.g., for frequencies of the oscillating member of a range of l to 30 cycles. Also the synchro nizing amplitudes may be varied over a wide range e.g., between 280 and 30.

A particularly favorable form of the adjunctive ele' ment is comprised of a thin plate, but it is also readily possible to provide this element in a different form such as a ferromagnetic powder that is dispersed in carrler.

Due to the bilateral vibrations of the oscillating mem ber it is advisable that the ferromagnetic element is dis posed symmetrically to the central plane of oscillation for generating identical conditions in both oscillating directions. It may be a single element disposed in this plane or with multiple adjunctive elements in and/or bilaterally of this central plane of oscillation.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of the invention will become apparent from the following description in connection with the drawings that contain exemplified embodiments of the invention. The drawings show:

FIG. 1 is an axial section through a first embodiment of the invention,

FIG. 2 is a section along the line 22 of FIG. 1,

FIG. 2a is a schematic representation ofa monitoring pulse generator in connection with the drive of the oscillating member,

FIG. 3 is a partial view showing a second embodi ment of invention, and,

FIG. 4 is a section along the line of 44 of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION In the first exemplified embodiment of FIGS. 1 and 2, there is disposed a mechanical oscillating member in the form of a balance assembly having a driving coil. The driving coil is energized by driving pulses of synchronizing frequency. Any optional pulse generator may be applied to generate these driving pulses, provided it is ensured that these pulses are of a constant frequency. A known generator of this type, which is preferably also used in connection with the synchronizing arrangement according to this invention, is schematically shown in FIG. 2a. In this scheme, 100 represents the pulse generator which may customarily be a crystal oscillator such as a quartz oscillator. The pulse generator 100 supplies control pulses to a number of frequency dividers 102, so that the control frequency is divided downwards and reduced to the desired low frequency. e.g. l to cycles. These low frequency control pulses are then fed to an output phase 104 where, by means of the control pulses. driving pulses of identical frequency are adjustingly fed in and then conducted to a driving coil 106 that coacts with a magnet 108. In this case either the coil 106 or the magnet 108 may be stationary; it is only necessary that the two components move relative to each other.

In the description of the exemplified embodiment it is assumed that driving pulses of synchronized frequency are fed to the driving coil as shown in the drawmgs.

Reference is also made to the fact that the mechanical and electromagnetic composition of the exemplified embodiments described hereinafter are to a great extent similar to already known types, so that a comparatively cursory description will be sufficient.

In the exemplified embodiment of FIGS. 1 and 2, there is disposed a mechanical oscillator in form of a balance assembly designated by 10. This balance assembly has a balance staff 12 mounted in bearings 14 and 16 of bridge members 18 and 20. The balance staff 12 carries the balance body 22 and also a hub 24 to which a driving coil 26 and an impulse pin 28 are secured. The balance body 22 is insulated against the balance staff 12 and on said body 22 and bridge member 20 there is secured a first spiral'spring 30. A second spiral spring 32 is secured to the other end of the balance staff 12 and to a frame section not shown.

Impulse pin 28 coacts with an escapement 34 pivotally mounted at 36 and with its escapement pins 38 engages in indexing wheel 42 securely mounted on wheel staff 40.

Driving coil 26 has parallel lengthwise sides 2611 and 26b and two arcuate sections 260 and 26d that join said sides together. Four pairs of permanent magnets 44, 46. 48 and 50 coact with said coil 26, with two pairs of said magnets always being secured to one back plate 52 or 54.

According to the embodiments of FIGS. 1 and 2, a single ferromagnetic adjunctive element 56 is secured to the one lengthwise coil side 26a, namely, on the peripheral surface and in the central plane of oscillation AA.

When the escapement is in oscillation and the driving pulses are fed to the driving coil, as described above, the effect of the ferromagnetic adjunctive element 56 is as follows. It is assumed that the balance assembly 10 v and with it the driving coil 26 oscillate with a constant synchronizing frequency of 6 cycles and. short driving pulses of identical frequency are conducted to driving coil 26 when passing through the zero point or position of oscillation, i.e. the zero point or position of oscillation between two half oscillations in two opposing directions which is also conventionally termed as the point of equilibrium or neutral position of oscillation and at which point the oscillating member and driving coil are oscillating at their highest velocity. As a result, the balance assembly 10 oscillates with synchronizing frequency and synchronizing amplitude. During this oscillation of e.g., to 200, the ferromagnetic adjunctive element 56 coacts sequentially with the several poles of the permanent magnets 44 to 50. For the sake of simplicity in the following discussion, only one magnet group with the pairs 44 and 46 will be considered, as the effect of the two other magnet pairs 48 and 50 is exactly the same.

As the adjunctive element 56 is a member having soft iron characteristics and thus without any permanent magnetism, the adjunctive element 56 is attracted by all magnets for example, first by the north pole and then by the south pole of magnet pair 44. Since the oscillating velocity of the balance assembly is very high, the effect of the adjunctive element 56 is insignificant. If, in addition thereto, the element oscillates beyond the south pole of magnet pair 44, then the adjunctive element 56 enters into a region in which oscillating velocity is substantially smaller and even passes through the zero velocity point. If the adjunctive element swings beyond the south pole of magnet pair 44, then when oscillating further up to the central plane of oscillation AA, a sort of braking force is exerted upon the driving coil; that is, the counteracting force of the spiral springs 30 and 32 is impaired. In passing through the central plane of oscillation AA, the magnetic attraction of the south pole 44 and the north pole 46 are approximately identical, so that the influence of the element is zero. Upon further oscillation towards the north pole of 46, the attraction of the adjunctive elealtering the spring force of the spiral springs, whereby the adjusting point also changes, i.e., the synchronizing amplitude, which latter must be no means be so wide '4 that the adjunctive element 56 swings as far as the central plane of oscillation.

As stated above, in deviations fromthe synchronizing amplitude, the frequency of the balance assembly changes and with that the magnitude of the driving pulses, which decreases with expanding amplitude and increases with contracting amplitude.

FIGS. 3 and 4 illustrate a further exemplified embodiment. In this case the pairs of fixed magnets are not shown, but they can be arranged in a manner similar to the first embodiment. Substantially only the balance assembly is shown which, e.g., oscillates at 4 cycles. The whole unit is designated by 62 and is mounted in bearings 64 and 66. There is a balance staff 68 to which one end of the spiral springs 70 and 72 are secured, the

other ends being secured to frame members 74 and 76.

The balance body in toto is designated 78. It has a hub and two forked arms 82 and 84 to which a driving is secured by two cast resin infusions 86 and 88. One ferromagnetic adjunctive element 92 and 94 is included in each cast resin infusion providing a pair disposed symmetrically with respect to the central plane of oscillation BB. Opposite the driving coil is a web 96 to which an arcuate member 98 is attached as a weight equalizing means.

The mode of operation of the pair of ferromagnetic adjunctive elements is the same as described in connection with the first exemplified embodiment. If the not shown pairs of fixed magnets are disposed symmetrically to the central plane of oscillation BB which also forms a radial line that passes through the axis or staff 68 of the oscillating member, the center of the driving coil 90 and through the zero point of oscillation B, then in this case also, the adjunctive elements 92, 94 will be zeroed in an oscillation of in which the counterforce of the spiral springs will not be affected.

The arrangement of the magnets, the adjunctive elements, and, if desired, also multiple driving coils, may be diversified in a number of ways. But regard must be given to the fact that the influence of the ferromagnetic adjunctive elements bilaterally of a specific amplitude which is then the synchronizing amplitude will cause an inverse change of synchronizing frequency if amplitude changes.

The modeof operation of the ferromagnetic adjunctive elements is independent of the type of relative oscillation between the magnetic coil and the magnets. For example, the driving coil may be stationary and the permanent magnets disposed on the balance assembly. In this case it is not necessary that the adjunctive elements be mounted on the driving coil proper, rather, they may be secured to any optional stationary memher.

It is to be understood that the above-described arrangements are merely illustrative examples of the application. Numerous other arrangements may be readily devise by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

We claim:

1. A synchronizing arrangement for a time-keeping instrument including an electromechanical actuating device for driving the instrument having a control system which includes at least one driving coil movable in relation to a fixed permanent magnet system .by means of which control system a driving coil carried on a mechanical oscillating member rotatable about a axis can beset into motion on either side of a zero point of oscil- LII lation predetermined central between two opposite extreme positions of oscillation of said driving coil and substantially at which point a drive impulse is coupled to 's aid driving coil with constant synchronizing frequency through a selected synchronizing amplitude, said oscillation being opposed by a spring member coupled to said oscillating member exerting a substantially constant counterforce in such manner that with said driving coil being disposed at said synchronizing amplitude said oscillating member then having zero oscillating velocity and a pulse generator for generating electrical control pulses coupled to means for dividing down the frequency of the control pulses and feeding said pulses to the coil of said control system wherein the improvement comprises: at least two separate ferromagnetic adjunctive elements each being mounted in a fixed geometric relation on said oscillating member in such manner that with said driving coil being disposed symmetrical with respect to a radial line passing through said axis and the center of said driving coil and said zero point of oscillation said adjunctive elements each being then disposed remote nd symmetrical on each side of said radial line and peripheral with respect to said driving coil and with said driving coil being disposed approximately at said selected synchronizing amplitude said adjunctive elements only then being disposed with respect to said fixed magnet system to generate a synchronizing force through cooperation with said fixed magnet system which is dependent upon amplitude variations from said synchronizing amplitude for adjustment of the frequency of said mechanical oscillating member. 2. A synchronizing arrangement in accordance with claim 1 wherein:

said ferromagnetic adjunctive members coact with the permanent magnet system during the relative movement of said system and the driving coil to generate a nonlinear synchronizing force for rapid adjustment of the mechanical oscillating member. 3. A synchronizing arrangement in accordance with claim 1 wherein:

said ferromagnetic adjunctive members generate a synchronizing force which adjusts oscillator frequency in a nonlinear manner as the amplitude vanes. 4. A synchronizing arrangement in accordance with claim 1 wherein:

said ferromagnetic adjunctive members are provided such that in the adjusting range the change in oscillating frequency as a function of the change in amplitude is relatively large. 5. A synchronizing arrangement in accordance with claim 1 wherein:

claim 1 wherein:

the ferromagnetic element comprises a material having a small hysteresis loss.

9. A synchronizing arrangement in accordance with claim 1 wherein:

the oscillating member has a synchronizing frequency in the range of l to 30 cycles. 10. A synchronizing arrangement in accordance with claim 1 wherein:

the oscillating member has a synchronizing amplitude ranging from 280 to 30. 

1. A synchronizing arrangement for a time-keeping instrument including an electromechanical actuating device for driving the instrument having a control system which includes at least one driving coil movable in relation to a fixed permanent magnet system by means of which control system a driving coil carried on a mechanical oscillating member rotatable about a axis can be set into motion on either side of a zero point of oscillation predetermined central between two opposite extreme positions of oscillation of said driving coil and substantially at which point a drive impulse is coupled to said driving coil with constant synchronizing frequency through a selected synchronizing amplitude, said oscillation being opposed by a spring member coupled to said oscillating member exerting a substantially constant counterforce in such manner that with said driving coil being disposed at said synchronizing amplitude said oscillating member then having zero oscillating velocity and a pulse generator for generating electrical control pulses coupled to means for dividing down the frequency of the control pulses and feeding said pulses to the coil of said control system wherein the improvement comprises: at least two separate ferromagnetic adjunctive elements each being mounted in a fixed geometric relation on said oscillating member in such manner that with said driving coil being disposed symmetrical with respect to a radial line passing through said axis and the center of said driving coil and said zero point oF oscillation said adjunctive elements each being then disposed remote nd symmetrical on each side of said radial line and peripheral with respect to said driving coil and with said driving coil being disposed approximately at said selected synchronizing amplitude said adjunctive elements only then being disposed with respect to said fixed magnet system to generate a synchronizing force through cooperation with said fixed magnet system which is dependent upon amplitude variations from said synchronizing amplitude for adjustment of the frequency of said mechanical oscillating member.
 2. A synchronizing arrangement in accordance with claim 1 wherein: said ferromagnetic adjunctive members coact with the permanent magnet system during the relative movement of said system and the driving coil to generate a nonlinear synchronizing force for rapid adjustment of the mechanical oscillating member.
 3. A synchronizing arrangement in accordance with claim 1 wherein: said ferromagnetic adjunctive members generate a synchronizing force which adjusts oscillator frequency in a nonlinear manner as the amplitude varies.
 4. A synchronizing arrangement in accordance with claim 1 wherein: said ferromagnetic adjunctive members are provided such that in the adjusting range the change in oscillating frequency as a function of the change in amplitude is relatively large.
 5. A synchronizing arrangement in accordance with claim 1 wherein: said ferromagnetic adjunctive members are provided such that in the adjusting range the change in oscillating frequency is approximately proportional to the change in amplitude.
 6. A synchronizing arrangement in accordance with claim 1 wherein: the ferromagnetic element comprises a material having a small hysteresis loss.
 7. A synchronizing arrangement in accordance with claim 1 wherein: the ferromagnetic elements comprise a ferrite material.
 8. A synchronizing arrangement in accordance with claim 1 wherein: the permanent magnet system includes at least two groups of pairs of magnets disposed symmetrically to the central plane of oscillation so that the ferromagnetic adjunctive element coacts therewith.
 9. A synchronizing arrangement in accordance with claim 1 wherein: the oscillating member has a synchronizing frequency in the range of 1 to 30 cycles.
 10. A synchronizing arrangement in accordance with claim 1 wherein: the oscillating member has a synchronizing amplitude ranging from 280* to 30*. 